31.2.10 Hook

Hook functions manage system hooks, which are shared resources that install a specific type of filter function. A filter function is an application-supplied callback function, specified by the SetWindowsHook function, that processes events before they reach any application's message loop. Windows sends messages generated by a specific type of event to filter functions installed by the same type of hook. The following list briefly describes each hook function:

Function Description

CallMsgFilter Passes a message and other data to the current message-filter function
CallNextHookProc Calls the next hook in the chain
CallWndProc Filters messages sent by SendMessage
SetWindowsHook Installs a system or application filter function
SetWindowsHookEx Installs a system or application filter function
UnhookWindowsHook Removes a Windows filter function from a filter-function chain
UnhookWindowsHookEx Removes a system or application filter function